Reality check

Film - Mark Kermode on a sci-fi adaptation of a story Philip K Dick never got round to writing

The cult sci-fi novelist Philip K Dick died in 1982, the same year that Ridley Scott's Blade Runner achieved the seemingly impossible task of bringing the author's peculiar brand of paranoid existentialism to the screen. A tale of an android-hunter who falls in love with a robot and then discovers that he may himself be a replicant, Blade Runner (from the novella Do Androids Dream of Electric Sheep?) set the template for a string of PKD-inspired cinema fantasies including Total Recall, Impostor and Min-ority Report.

While it's impossible to know what Dick would have made of any of these films other than Blade Runner (of which he approved), it is intriguing to imagine the paranoid meltdown that Vincenzo Natali's Cypher might have provoked in his hyperactive mind. Because, despite its crystalline cinematic distillation of a classic Dick narrative (all "alternate realities" and "artificial personalities"), PKD would have had no memory of writing Cypher, which is, in fact, based entirely on an original script by the feature first-timer Brian King. Indeed, this may be the finest screen adaptation of a story never written by Philip K Dick.

The set-up for Cypher is classic PKD: a schlubby accountant, Morgan Sullivan (Jeremy Northam), cast adrift in an anonymous grey-washed future of monolithic architecture and impersonal work-spaces, seeks escape from his humdrum existence by becoming an industrial spy for a vast multinational, Digicorp. Having passed a series of intrusive psych-tests designed to weed out counter-spies from rival corporations, Morgan is invited to adopt a new identity - Jack Thursby (whose surname makes knowing reference to The Maltese Falcon) - and is ready to work as an industrial snoop. But after a chance meeting with an exotic femme fatale called Rita (Lucy Liu), Morgan/Jack discovers that there's more to his new life than meets the eye (or indeed the mind), and begins to spiral into a world of self-doubt in which not only his actions, but his very identity, become matters of confusion and intrigue. One minute he's attending marketing conventions for everyday toiletry products, the next he's hanging out of helicopters, dodging bullets and escaping a range of adversaries, all of whom want to use and abuse his shifting grip on reality.

Natali laid some of the philosophical groundwork for Cypher in his first feature, Cube, an ambitious existential nightmare in which six people are inexplicably trapped in a giant mechanical puzzle. Shot for peanuts in a Toronto warehouse, but boasting a spectacular visual style, this promising Kafka-esque puzzle came a cropper in the casting.

There are no such problems this time round, with Cypher benefiting from the presence of Jeremy Northam, who steps effortlessly into the complex central role of Morgan/Jack, providing an enigmatic conundrum at the heart of the drama whose blend of bafflement and dawning awareness is both engaging and alienating. Although better known for a string of classic gentlemanly roles in such period dramas as Enigma, An Ideal Husband and The Winslow Boy, Northam already has a devoted genre following thanks to his winning turn in Guillermo del Toro's flawed mutant-bugs movie Mimic. Here, he proves himself a true sci-fi star, pitching his performance perfectly between credible naturalism and arch knowingness - you feel that he understands as well as inhabits the film's necessarily "empty" and "insubstantial" anti-hero, enabling the audience to remain locked into his perspective even as the plot spirals into insanity. Lucy Liu, a star of Charlie's Angels, is less assured dramatically, but her striking presence (chiselled cheekbones, piercing eyes, feline movements) provides the collision of glamour, threat and uncertainty to sustain the pervasive air of creeping paranoia.

Where some other Dick-ensian screen fantasies have failed to marry stylish visuals with thematic substance, Cypher maintains a healthy balance between intellectual provocation and visual stimulation, with King's script boldly venturing where blockbusters such as The Matrix: reloaded have notably feared to tread. There may be a touch too much cineliteracy in Natali's direction (references to Alfred Hitchcock's North by North-west, Jean-Luc Godard's Alphaville, John Frankenheimer's Seconds and Terry Gilliam's Brazil are all there for those who wish to find them) but like Darren Aronofsky's ground-breaking Pi, Cypher ultimately conjures a world which is uniquely its own. "Reality," Philip Dick famously pronounced, "is that which, when you stop believing in it, doesn't go away." Dick would have believed in Cypher - although he may well have had a nervous breakdown trying to figure out how space-aliens broke into his head and stole a story he hadn't even got round to writing yet.

Cypher (15) opens in London on 29 August and nationwide on 5 September

Philip Kerr is away